Our own boards: one platform for every IEMI product
What we learned on the bench (3 Nov 2026). Building products from hobby boards, ribbon cables and adapters does not scale:
- On our test board, a camera ribbon that looked right reversed every pin and overheated the board.
- Adapters and plugs can work loose in equipment that takes hits.
- Batteries need protection boards wired by hand.
- Every unit needs its sensors set up by hand.
That is fine for one test stump. It is not fine for 20+ products, at least 10 units each, growing to 10,000.
What we decided:
- We design our own circuit boards.
- An assembly house makes and tests them.
- We manage the software ourselves: one image, written to every unit at the factory.
Numbers marked est. are estimates; vendor quotes come next.
1. Two core boards, not 24
We checked the parts list of every one of our 24 products, and they fall into two groups:
| Group | What the product needs | Products |
|---|---|---|
| Vision | camera(s) and on-device AI | CellOne, AthleticsOne, RacketOne, ChillOne, StudyOne, CricketOne, DockOne, DiamondOne, PoolOne, ClassOne, FarmOne, BayOne, PumpOne, FootballOne, GarageOne, AisleOne, CourtOne, RoadOne, SiteOne |
| Sensor | radar, distance and climate sensors, no video | RoomOne, DampOne, KitchenOne, BedsideOne, CareOne (and the small parts of AthleticsOne, RacketOne, DiamondOne, FootballOne) |
Every product becomes one of these core boards plus a small product-specific board or a different set of fitted parts. About four board designs cover all 24 products:
| Board | What is on it | Used by |
|---|---|---|
| IEMI Vision V1 | our own RV1126B core circuit (quad-core, 3 TOPS AI, camera processor): the chip, memory, storage and power placed straight on our board, with Wi-Fi/Bluetooth, motion sensor, security chip, ID chip and the battery system | most Vision products, CricketOne first |
| IEMI Vision V2 (later) | our own RK3576 core circuit (6 TOPS, for more cameras), same approach | AisleOne, ClassOne, DockOne, BayOne, RoadOne, SiteOne |
| IEMI Sensor S1 | ESP32-S3 radio module (already certified for its radio), radar, distance and climate sensors as fit options, power block. Set on RoomOne’s board (3 Nov 2026): ESP32-S3-WROOM-1-N8R8 soldered by its edge pads, BGT60TR13C 60 GHz radar chip, BMV080 + SCD41 + SGP41 + SHT45 air chips in a slotted air corner, ATECC608B, ID chip, factory pads; see it | all Sensor products, and the sensor parts of the Vision products |
| IEMI Camera C1 | the camera chip and lens on a section of the same board, joined by the board’s own flex (no camera cable) | every Vision product |
Our own chips on our own board, in each product’s own shape
We do not buy computer boards or modules and plug them together. Each product gets one board of its own, made in the shape of the equipment: rigid where chips sit, flexible where it bends. On it:
- the processor, memory and storage;
- Wi-Fi and Bluetooth;
- the camera chip;
- the battery charger, protection and gauge;
- the sensors and the security chip.
The core circuits (V1, S1, C1) are designed and proven once, then copied into each product’s shape. Every product reuses the same memory and power layout and the same software.
- CricketOne’s board is the first (see it). It is one rigid-flex piece that folds into the stump: a camera head, a 28 mm-wide brain on the heat bar, a flex tail to the cells, and a base disc with the charger.
- The hardest part is the RV1126B’s memory and power layout. We start from Rockchip’s hardware design guide and reference schematic, and an engineer experienced with Rockchip boards reviews it.
- Software is developed on an RV1126B development kit while the first boards are made.
- We compared ready-made RV1126B modules (Boardcon Tiny1126B 34 × 30 mm, Forlinx FET1126Bx-S 40 × 40, Graperain GR1126B 42 × 42). They need plugs or a carrier board, and cannot take each product’s shape.
What this fixes
| Problem we hit | How the platform fixes it |
|---|---|
| A camera cable that reversed every pin | No camera cable at all: the camera chip is on the same board. Every board’s first power-on is current-limited on the factory fixture, which finds a short in about 1 s and cuts the power. |
| Adapters and plugs working loose | No plugs inside the product: one board with rigid and flexible sections, cells soldered on. |
| Heat | The heat path is part of the board design: the processor sits on a copper area joined through a thermal pad to the equipment’s shell. |
| A battery with no protection | Every board has the same power block: battery charger, protection that cuts off a flat cell, battery gauge, reverse-polarity protection and a solar input option. |
| Setting up each unit by hand | An ID chip on each board stores the product, the board version and the serial number. The factory fixture tests and calibrates every unit and records the results. |
2. One software image for all products
- One image per core board, built automatically from our code: Linux from Rockchip’s (or Espressif’s) SDK, plus our layer.
- The product is read at boot from the ID chip: CricketOne, CellOne and so on. The board loads that product’s program, AI models and calibration. This matches our single phone app, which already has an edition per product.
- A security chip on every board holds that unit’s own key. Every call the equipment makes is signed, and the key is written at the factory, never by hand.
- Updates arrive over Wi-Fi into a second copy of the system. A bad update rolls back by itself, and updates never install during a match.
3. SD cards for development, built-in storage for sale units
During development and the first pilots, software goes on SD cards. Swapping a card is the fastest way to try a new build.
Units we sell boot from the board’s own built-in storage (eMMC) instead. A card in equipment that takes hits can lose contact, cheap cards wear out from constant logging, and a removable card weakens the signed-call security. The software is the same; only where it is stored changes. The factory writes it over USB in about 2 minutes (est.), and from then on updates arrive over the air.
4. Who does what
| Work | Who |
|---|---|
| What each product’s board must do, block diagrams, parts choice, and a check of every part that plugs into another | IEMI Labs |
| Schematics and layouts (KiCad) | IEMI Labs; an experienced hardware engineer reviews and signs off every board before it is made |
| Making and assembling the boards | JLCPCB / PCBWay for the first boards and pilots; a contract manufacturer from about 1,000 units |
| Software image, drivers, product programs, updates | IEMI Labs, from the chip makers’ SDKs |
| Factory test fixture: spring pins, current-limited first power-on, camera/radar/motion checks, software and key writing, calibration, label | designed and programmed by IEMI Labs; copies built by the manufacturer |
| Radio, safety and battery certification | an accredited test lab, with our test plan and files |
| Shells | our CAD: 3D-printed now, moulded at volume |
5. Board cost per unit (est.)
| Board | qty 10 | qty 1,000 | qty 10,000 |
|---|---|---|---|
| V1 Vision core (chip, memory, storage, power, radio, security chip) | $90–120 | $50–65 | $38–50 |
| C1 Camera (global-shutter sensor + lens + cable) | $25–40 | $12–18 | $8–12 |
| S1 Sensor core (radio module + radar + sensors + power) | $30–45 | $12–18 | $8–12 |
At qty 10 our own Vision board costs about the same as today’s hobby board, camera, adapters, boost and charger boards. It needs no hand wiring and passes the same factory test every time. From 1,000 units it is cheaper.
6. Timeline
| When | Step | Done when |
|---|---|---|
| Nov 2026, wk 1–2 | Board requirements for each product; RV1126B development kit; Rockchip hardware design guide | V1, S1 and C1 specs fixed |
| Nov 2026, wk 2–5 | CricketOne’s camera and tracking software running on the RV1126B development kit | same code, same calls as on the test stump |
| Nov–Dec 2026, wk 3–8 | CricketOne schematics and layouts (rev A), reviewed and signed off | files ready to make |
| Jan–Feb 2027 | Rev A boards made (rigid-flex about 2–3 weeks) and brought up on our fixture | every block works, or its faults are listed |
| Mar–Apr 2027 | Rev B and the factory test software | boards pass the fixture with no hand work |
| Apr 2027 | Pilot units on real sites; pre-compliance radio scan | units in use |
| Apr–Jun 2027 | Certification | test reports in hand |
| about Jun 2027 | First sales | |
| mid-2027 | Contract manufacturer for 1,000+ units | the manufacturer runs our fixture |
| 2028 | Moulded shells, larger runs | lower cost per unit |
CricketOne goes first (its boards). Then each product gets its own board sheet, one per lab run, in the order in the table below.
7. Board sheet for every product
Each product gets a board sheet and its board as code (like CricketOne’s hardware/pcb/stump-board.mjs: its own shape, every part placed and checked): which core circuits it uses, every connector and cable (keyed, latched, never an adapter), the power budget, the heat path, the factory tests and the cost.
| # | Product | Core | Board sheet |
|---|---|---|---|
| B0 | CricketOne | V1 + C1 | [x] CricketOne boards |
| B1 | CellOne | V1 + C1 | [x] CellOne boards |
| B2 | RoomOne | S1 | [x] RoomOne boards |
| B3 | AthleticsOne | V1 + C1 + S1 | [x] AthleticsOne boards |
| B4 | RacketOne | V1 + C1 + S1 | [x] RacketOne boards |
| B5 | DampOne | S1 | [x] DampOne boards |
| B6 | ChillOne | V1 + C1 | [x] ChillOne boards |
| B7 | KitchenOne | S1 | [x] KitchenOne boards |
| B8 | BedsideOne | S1 | [x] BedsideOne boards |
| B9 | StudyOne | V1 + C1 | [x] StudyOne boards |
| B10 | DockOne | V2 + C1 + S1 | [x] DockOne boards |
| B11 | CareOne | S1 | [x] CareOne boards |
| B12 | DiamondOne | V1 + C1 + S1 | [x] DiamondOne boards |
| B13 | PoolOne | V1 + C1 + S1 | [x] PoolOne boards (S1 added: the hinge camera is 1.1 m from the brain, so its frames go over the wired link) |
| B14 | ClassOne | V2 + C1 | [x] ClassOne boards (main board, camera tabs and light strip in the header rail; air board and tray board on one latched bus, because the CO2 chip must sit 3 to 6 ft up and the tap-in at a child’s reach) |
| B15 | FarmOne | V1 + C1 + S1 | [x] FarmOne boards (S1 added: the trough runs on a 6 W panel, so an always-on ESP32-S3 wakes the RV1126B when stock come; main and power wings round the water meter, camera and heat tabs behind the water-side face) |
| B16 | BayOne | V2 + C1 | [x] BayOne boards (main board on the head floor, back strip with the bay and heat cameras, radar strip, front board with the aspects, approach camera and LTE-M, power board with mains, the backup cell and the fire-panel relay; the bay and heat windows moved to the back wall) |
| B17 | PumpOne | V1 + C1 | [x] PumpOne boards (main board with the camera and radar tabs and a power board with the station inputs on the right side wall, door board with the heat chip, e-paper and call light; the antenna moved outside the stainless box) |
| B18 | FootballOne | V1 + C1 + S1 | [x] FootballOne boards (one spine in all four posts with the pitch camera, the global-shutter goal-line camera, four cells and the call lights; a crossbar board with the ESP32-S3 for the wrist unit; the goal-line camera moved up to 2.0 m) |
| B19 | GarageOne | V1 + C1 | [x] GarageOne boards (main board behind the door-end wall with the camera tab and two light strips on the side walls, power board at the back end with the heat-camera tab, the opener link and the mains; the vents moved to the back wall) |
| B20 | AisleOne | V2 + C1 | [x] AisleOne boards (the same set in both runs: main board with two 12 MP camera tabs and the light strip at the middle of the canopy, end light boards at the run’s ends, a power board on the canopy light feed; the cameras moved from 1 m ribbons at the run’s quarters to the middle, turned out) |
| B21 | CourtOne | V1 + C1 + S1 | [x] CourtOne boards (main board with the top camera head in the top rail, a corner camera board in each side rail looking out of the side faces, a rim board in the ring box, 29 light sections, and the digit and power boards in the clock box; the top window became an 18 × 39 slot and the corner windows moved to the side faces) |
| B22 | RoadOne | V2 + C1 | [x] RoadOne boards (behind the head’s own LED modules: main board on the head floor, a corner board with the approach camera behind the door’s bottom corner, a back strip with the kerb radar, call lights and radios, a side strip with the crossing camera, and a power board on an unswitched feed that senses the lamp feeds without touching them; the approach camera moved from the floor to the door corner) |
| B23 | SiteOne | V2 + C1 + S1 | [x] SiteOne boards (S1 added: the site camera and the reader head sit 1.2 and 1.8 m from the processor, too far for a camera ribbon, so each is an ESP32-S3 node on RS-485; main board with the radar tab under it and the street strip with the entry camera near the street wall, site, side, power and reader boards; puck antenna through the steel lid) |
8. Risks
| Risk | What we do |
|---|---|
| The CricketOne camera driver on the RV1126B | proven on the development kit before any schematic is fixed |
| A chip is discontinued | every chip is chosen with a second source or a long-life (industrial) grade where one exists |
| The RV1126B memory and power layout | started from Rockchip’s reference design and reviewed by a Rockchip-experienced engineer before rev A is made |
| First boards have faults | expected, and a second version is planned; the current-limited first power-on protects every board |
| Certification fails | pre-compliance scans at the pilot; radio modules that are already certified, used with their approved antennas |
Sources
- Boardcon Tiny1126B, 34 × 30 mm RV1126B module
- Forlinx FET1126Bx-S, 40 × 40 mm
- Graperain GR1126B, 42 × 42 mm
- MYIR MYC-LR3576 RK3576 module
- JLCPCB prototype assembly cost
- Host-product testing with certified radio modules
Lessons every board shares (4 Nov 2026)
CricketOne leads, and every lesson any board teaches becomes a rule that every board is checked against on the next run (products/_shared/board-rules.mjs). Each product page shows its board’s review under “Checked before we order”, and each board has a quote pack written from its parts and review.
- Battery: counted for a full 10-hour day with cells aged to 80 % and cold.
- Charging: one night (9 h) puts back a full day; a thermistor holds charging outside the cells’ range.
- Clocks: MEMS oscillators, not quartz, where the product takes 1,000 g or more.
- Software on the card: a hinged, latched microSD socket fitted on every board, and our software starts from it with no setup.
- Underfill under ball-grid chips where the product takes shocks.
- Sun: the finish sets the cell temperature in full sun.
- Cameras: pixels on the smallest target at the farthest distance, smear at top speed, data rate against the link, and frame rates the chip really has.
- Timed calls: cameras share a frame-sync line, with a real-time kernel.
- Clip memory: 3 s or more of raw video kept for an unsure call.
- Antennas near metal are measured on rev A.
- Conformal coating outdoors, in bathrooms and near water.
- Check the part number against the datasheet: the MLX90640 BAA is the 110° heat camera, the BAB the 55° one (fixed on DampOne and in PumpStation’s buy list, 4 Nov 2026).
- Antennas outside metal boxes: a radio inside a closed metal enclosure fails the review unless its antenna is outside the metal; PumpOne’s LTE-M antenna moved from inside the stainless panel to a sealed puck through the top wall, and every board with a radio in metal now names its window (4 Nov 2026).